JP2002062725A - Developing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device, capable of preventing toner from being embedded in the surface of a developer carrier by carrier in the case of using two-component developer and preventing the developer carrier from being soiled due to the fusion of the toner, thereby stably obtaining a proper- image quality over a long time. SOLUTION: This developing apparatus possesses developer carrier provided with projecting and recessed parts on its surface, set so that the average crest interval of the projecting and recessed parts are 1/3 to 6 times as large as those of the weight average particle size of the magnetic carrier of the two- component developer, set so that the ten-point average roughness of its surface is 1/10 to 1/2 times as large as that of the weight average particle size of the magnetic carrier and constituted, so that the existing number of the recessed parts whose width is 1 μm to 10 μm and whose depth is >=0.2 μm is under ten at the interval of 100 μm in the profile of the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying method using an electrophotographic method or an electrostatic recording method in which a latent image formed on an image carrier is made visible by attaching toner in a two-component developer. And a developing device used in an image forming apparatus such as a laser beam printer. In particular, the present invention relates to a developing device having an improved developer carrier used for transporting the developer.

[0002]

2. Description of the Related Art An electrophotographic latent image formed on an image carrier such as a photosensitive drum is made visible by attaching toner in a developer, such as an electrophotographic copying machine or a printer. A developing device used in an image forming apparatus uses a developing sleeve (developer carrying member) such as a metal developing sleeve as a developer carrying member, and carries the developer contained in a developing container on the developing sleeve. Then, the electrostatic latent image formed on the image bearing member is transported to a developing area facing the image bearing member, and the electrostatic latent image formed on the image bearing member is developed with a toner in a developer to visualize the latent image.

[0003] Developers include a magnetic one-component developer made of a magnetic toner, a non-magnetic one-component developer made of a non-magnetic toner, and a two-component developer containing a non-magnetic toner and a magnetic carrier. The material and shape of the developing sleeve are selected depending on the type. In the case of a two-component developer, a developing sleeve provided with a magnetic field generating means such as a magnet is used, and a nonmagnetic metal such as stainless steel or aluminum is mainly used as the material.

In the above-described developing device, the surface of the developing sleeve is roughened so that a non-magnetic toner (hereinafter, also simply referred to as “toner”) and a magnetic carrier (hereinafter, simply referred to as “toner”) are formed.
This improves the transportability of the two-component developer constituted by the “carrier”) to the developing area, and also allows a uniform developer layer to be coated on the surface of the developing sleeve.

[0005] As a method of roughening the surface of the developing sleeve,
A sandpaper method in which the surface of the developing sleeve is rubbed with sandpaper, a sandblast method using irregular shaped particles, a mixing method thereof, a chemical etching method by chemical treatment, and the like have been proposed and implemented.

[0006]

However, the conventional developing sleeve has the following problems. In the developing sleeve roughened by the above-mentioned various methods, the toner or the components in the toner are liable to be caught and adhered to valleys (concave portions) of the unevenness formed on the roughened surface over a long period of use. The toner adhered to the valley is easily fused by friction heat generated by pressing the layer thickness regulating member that regulates the layer thickness of the developer on the surface of the developing sleeve over a long period of use, and the surface of the developing sleeve may be contaminated with the toner. There is.

Further, when a two-component developer containing a carrier is used, if there is unevenness on the surface of the developing sleeve, toner or a component in the toner is formed on the roughened surface by pressing of the carrier. (Especially in narrow valleys). The toner embedded in the valley is fused to the developing sleeve after a long use, and the surface of the developing sleeve is easily contaminated with the toner.

In recent years, in response to a demand for high image quality and a reduction in power consumption of a copying machine or a printer due to an increase in demand for a color copying machine or a color printer, the toner has been reduced in particle size and softening point. Accordingly, in the developing sleeve roughened by the above-described various methods, the toner or a component in the toner fuses to the uneven portion of the roughened surface due to long-term use, and the tendency to cause contamination becomes stronger. .

When toner fusion occurs on the surface of the developing sleeve, the amount of developer transported to the developing area decreases, and the image density decreases. Conventionally, a developing bias of a DC voltage and / or an AC voltage is applied to the developing sleeve at the time of development in order to perform favorable development. A high-resistance layer is formed by the fused material, and a desired electric field is not formed in a developing region between the developing sleeve and the image carrier during development.

Particularly, in a developing method which is adopted for the purpose of achieving high image quality with a small size by using a two-component developer, a thin layer of the developer is formed, the distance between the developing sleeve and the photosensitive drum is made 1 mm or less, and the DC voltage is reduced. In the developing method in which the AC voltage is superimposed and applied, an electric field generated between the developing sleeve and the photosensitive drum causes the toner on the surface of the developing sleeve to fly and develop, thereby obtaining a sufficient density. The impact is great. As a result, a sufficient developing effect by the developing bias on the toner on the surface layer of the developing sleeve cannot be obtained,
An image defect such as a density drop or white spots is likely to occur.

In fact, a non-contaminated developing sleeve and a contaminated developing sleeve were prepared, and an image evaluation was performed using the same developer. Concentration 0.2
And image defects such as white spots occurred.
This indicates that contamination of the surface of the developing sleeve due to fusion of the toner to the surface of the developing sleeve clearly causes a decrease in density and an image defect.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to prevent toner from being embedded in the surface of a developer carrying member by a carrier when a two-component developer is used, and to form a developer carrying member by fusing toner. An object of the present invention is to provide a developing device which does not cause contamination and thereby can stably obtain a high-quality image for a long period of time.

[0013]

SUMMARY OF THE INVENTION The present invention is used in an image forming apparatus provided with means for forming an electrostatic latent image corresponding to an image information signal on an image carrier. A developing device having a developer carrier that carries a two-component developer containing a non-magnetic toner and a magnetic carrier and transports the developer to a development area in order to form an image by developing an image; Irregularities are provided on the surface of the body, and the average peak interval (Sm) of the irregularities is set to 1/3 to 6 times (D / 3 ≦ Sm ≦ 6D) the weight average particle diameter (D) of the magnetic carrier. And the ten-point average roughness (R
z) is set to 1/10 to 1/2 times the weight average particle diameter (D) of the magnetic carrier, and in the profile of the surface of the developer carrier, the width is 1 μm to 10 μm and the depth is 0.2 μm. The present invention relates to a developing device wherein the abundance of the concave portions is less than 10 in an interval of 100 μm.

With this developing device, when a two-component developer is used, the toner is prevented from being embedded in the surface of the developer carrier by the carrier, and the developer carrier is not contaminated by the fusion of the toner. As a result, the image quality can be stably guaranteed for a long period of time, and the object of the present invention is achieved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a developing device used in an image forming apparatus for forming an image by developing an electrostatic latent image carried on an image carrier with a developer, comprising: When a two-component developer containing a non-magnetic toner and a magnetic carrier is used, it is possible to prevent the toner from being carried on the developer carrier for a long period of time, thereby preventing the toner from being fused on the developer carrier. This is a developing device capable of preventing adhesion and achieving stable supply of a high-quality image by the image forming apparatus.

The developer carrier carries a developer for developing an electrostatic latent image on the image carrier and transports the developer to a development area. surface)
Is provided with peaks and valleys by unevenness. The surface shape of the developer carrier is represented by a curve due to the unevenness in the cross section of the developer carrier (hereinafter, this curve is also referred to as a “cross-sectional curve”).
When expressed in the formula, the “mountain” refers to a portion of a cross-sectional curve within a certain range, which is higher than an average line of a roughness curve therein (hereinafter, this line is referred to as an “average line”). In other words, the “valley” refers to a portion that is recessed from the average line. The average line of the roughness curve is defined in JIS B0601.

Further, as shown in FIG. 3, the peak interval means a point at which a certain peak and another peak adjacent to the certain peak via a valley intersect with the average line on the valley side of the certain peak. Means the distance between another peak and a point at which the valley intersects with the average line on the opposite side, and the average peak interval refers to the average value of the peak intervals within a certain range.

The surface of the developer carrier has a width of 1 μm.
In some cases, a concave portion having a thickness of 10 μm to 0.2 μm or more (hereinafter, this concave portion is also referred to as a “micro concave portion”) may be formed. The minute concave portion may be at a peak or a valley as long as it satisfies the above range. The minute concave portion refers to a portion which is more concave than a line in which a fine convex portion in the fine irregularities is shaved and the fine concave portion is buried as compared with the peaks and valleys in the cross-sectional curve within a certain range. The width of the minute concave portion means a distance between intersections of the line and the cross-sectional curve. In addition, the depth of the minute concave portion refers to a distance between the line and a point where a perpendicular line of the line intersects a cross-sectional curve of the minute concave portion.

According to the present invention, the opportunity for contact between the toner and the carrier on the surface of the developer carrying member is improved, and the toner is prevented from being embedded on the surface of the developer carrying member. For a long time.

To improve the chance of contact between the toner and the carrier on the surface of the developer carrier, the average interval between peaks (Sm) and the ten-point average roughness (Rz) on the surface of the developer carrier are controlled within a predetermined range. Is achieved by setting Regarding the prevention of toner embedding on the surface of the developer carrier,
This is achieved when the number of the minute concave portions is less than 10 at intervals of 100 μm in the profile of the surface of the developer carrier. Hereinafter, each of these elements will be described.

The average mountain interval (Sm) qualitatively represents the interval between a certain mountain and an adjacent mountain. In general, when the average mountain interval is increased, the contact between the toner and the carrier on the surface of the developer carrier is improved. In the present invention, the average mountain interval is
The weight average particle diameter (D) of the magnetic carrier is preferably 1/3 to 6 times (D / 3 ≦ Sm ≦ 6D), and D / 2
It is more preferable that ≦ Sm ≦ 3D. If the average peak interval is smaller than the above range, the contact between the toner and the carrier becomes small, and the toner fusion cannot be sufficiently prevented. On the other hand, if the average mountain interval is larger than the above-mentioned range, the transportability of the developer by the developer carrier is reduced.

The ten-point average roughness (Rz) qualitatively represents a height difference between a peak and a valley. Generally, when the ten-point average roughness is small, the contact between the toner and the carrier on the surface of the developer carrier is improved. In the present invention, the ten-point average roughness is
1/10 times to 1 times the weight average particle diameter (D) of the magnetic carrier
/ 2 times. If the ten-point average roughness is smaller than the above range, the effect of catching on the surface of the developer carrier decreases, and the transportability of the developer decreases. Further, if the ten-point average roughness is too large than the above range, unevenness can be easily visually observed, so that the obtained image is likely to have unevenness, and the unevenness of the surface of the developer carrier may be uneven. The corresponding edge portion becomes very sharp, which affects the formation of carrier ears and easily affects image quality.

The minute recesses represent recesses into which toner easily enters or locks. Generally, when a minute concave portion is present, the minute concave portion is smaller than the carrier, so that the toner that has entered or locked in the minute concave portion is hard to come into contact with the carrier and is difficult to be separated from the minute concave portion. In the present invention, it is preferable that there are no more than 10 minute recesses at 100 μm intervals in the profile of the developer carrier. If there are 10 or more minute concave portions in the interval, the frequency of fusion of the toner existing on the surface of the developer carrier for a long period of time increases, and the surface of the developer carrier is contaminated, which may cause an image defect.

More preferably, the ten-point average roughness Rz is D / 6 ≦ Rz ≦ D / 2, where D is the average particle diameter of the magnetic carrier.
It has been found that the ratio within the range is good for preventing the contamination of the developer carrying member and improving the transportability of the developer. When the ten-point average roughness Rz of the surface of the developer carrier is D / 6 or more, the carrier is sufficiently caught by the irregularities on the surface of the developer carrier, and the frictional resistance between the developer and the developer carrier is increased. The agent transportability can be further improved. As described above, by further adjusting the ten-point average roughness Rz, it is possible to further suppress toner contamination on the surface of the developer carrying member, and to further improve the transportability of the developer.

The average peak interval, the ten-point average roughness, and the minute concave portion are not particularly limited as long as the measuring method or measuring instrument has a measurement limit capable of measuring at least the minute concave portion. The surface roughness can be measured by a known method of measuring surface roughness. As such a measuring method, for example, a contact type surface roughness meter (manufactured by
Examples thereof include a method using a surf coder SE-3300 manufactured by Kosaka Laboratories, and a method of analyzing and measuring from an electron microscope image near the surface in the cross section of the developer carrying member.

The developer carrier that satisfies at least the above three factors achieves good contact between the toner and the carrier and prevention of toner fusion on the surface of the developer carrier. Such a developer carrier can be formed by subjecting an elementary body (developer carrier before surface roughening) to a surface roughening treatment. The surface roughening treatment is preferably performed under appropriate conditions according to the material of the developer carrying member and the treatment method so as to satisfy the above-mentioned factors.

Examples of the surface roughening treatment include the sandpaper method, the sandblasting method, the chemical edging method, and the mixing method using two or more of these methods in the present invention. The surface can be roughened by a method or according to the method. In the present invention, it is preferable to employ a blast method.

The blasting material used in the blasting method may be selected depending on the physical properties of the material of the developer carrier. Examples of the blasting material include silica sand, river sand, cast iron grit, cast steel grit, and cut wire. , Alumina grit, silicon carbide grit, slag grit, and glass beads. It is preferable that the blast material is a blast material having a relatively small particle size and a blast material of a regular shape adjusted to a substantially spherical shape in order to suppress the formation of the minute concave portions.

Further, as a result of a detailed study including the type of the carrier, etc., the developer carrier was found to have a weight average particle diameter d (D ≦ d ≦ D ≦ 10 to 10D) of the magnetic carrier.
It has been found that the blast treatment with the shaped spherical particles having 10D) is better for preventing contamination of the developer carrier and improving the transportability of the developer. When the diameter d of the fixed spherical particles is equal to or larger than the average particle diameter D of the magnetic carrier, the frictional resistance between the developer and the developer carrier is increased, the transportability of the developer is improved, and the developer carrier is contaminated. Is also reduced.

When blasting is performed with regular spherical particles having a smaller diameter than the magnetic carrier, grooves (irregularities) are formed on the surface of the developer carrier as shown in FIG. It is not possible to penetrate deep into the upper spherical groove, and a gap is left between the magnetic carrier and the spherical groove on the developer carrier. Therefore, the magnetic carrier cannot be firmly caught in the spherical groove, and the magnetic carrier tends to roll on the groove on the developer carrier. Therefore, the frictional resistance between the developer and the developer carrier is resisted, and the conveying force of the developer carrier is likely to decrease.

On the other hand, when the particles are blasted with regular spherical particles larger than the magnetic carrier, grooves are formed on the surface of the developer carrier as shown in FIG. Can go all the way into the groove,
There is no gap between the magnetic carrier and the spherical groove on the developer carrier. Therefore, the magnetic carrier can be firmly caught in the spherical groove, and the magnetic carrier is hard to roll on the developer carrier. Therefore, it is considered that the frictional resistance between the developer and the developer carrier increases, and the transportability of the developer carrier is further improved. As described above, when the surface of the developer carrier is blasted with the regular spherical particles having a larger diameter than the magnetic carrier, the transportability of the developer by the developer carrier is improved.

Adjusting the weight average particle size of the regular spherical particles is also effective in preventing toner fusion. When blasting is performed with regular spherical particles having a smaller diameter than the magnetic carrier, a gap is easily formed between the magnetic carrier and the spherical groove on the developer carrying member as described above. The toner that has entered the gap can be scraped from the groove by contact with the magnetic carrier. However, in the former case, it is difficult to enter the magnetic carrier as it contacts the bottom of the groove, and the toner that has entered the gap is scraped. Since the toner cannot be removed, the toner tends to stay in the gap. As a result, the residual toner tends to accumulate heat and fuse.

On the other hand, when the surface of the developer carrier is blasted with regular spherical particles having a diameter larger than that of the magnetic carrier, as shown in FIG. 9, the magnetic carrier reaches the bottom of the spherical groove on the developer carrier. It can enter and there is no gap between the magnetic carrier and the spherical groove on the developer carrier. Therefore, in the process of circulating the carrier, the toner adheres to the carrier and is carried, and the toner does not remain on the surface of the developer carrying member. As a result, contamination is less likely to occur.

However, the carrier forms ears on the developer carrying member. The distance between the ears in this spike depends on the magnetic force, the carrier diameter or the magnetization of the carrier, but when a magnetic ferrite carrier is used, the magnetic brush is formed by arranging the magnetic ferrite carriers at intervals of about 10 times the carrier diameter. If the diameter of the regular spherical particles exceeds 10 times the diameter of the carrier, the ears of the magnetic brush become random, and the layer of the developer tends to be uneven due to the unevenness. From the above viewpoints, it is preferable that the weight average particle diameter of the fixed spherical particles is not less than the weight average particle diameter of the magnetic carrier and not more than 10 times this weight average particle diameter.

In addition, spherical glass beads or regular spherical particles as blast particles used in the present invention have an approximate shape such that an arc-shaped groove can be formed on the surface of the developer carrier when the developer carrier is blasted. Spherical particles are also included.

The blast treatment of the developer carrying member will be specifically described by way of an example. For example, blasting is performed by preparing glass beads as regular spherical particles. The blasting process is performed by moving a blast nozzle having a diameter of 7 mm, which is 100 mm away from the developer carrier, in parallel with the axis of the developer carrier with respect to the developer carrier rotating at 12 rpm. To air pressure (blast pressure) 3
Glass beads are sprayed on the surface of the developer carrier at kg / cm ² . In this way, the surface of the developer carrying member is subjected to the blast treatment, and the surface is roughened.

After the completion of the blasting, the surface of the developer carrier is washed and dried. Conditions such as the rotation speed, the distance of the blast nozzle from the developer carrier and the blast pressure can be appropriately changed depending on the material of the developer carrier base tube, and the like.
The blast conditions are not limited to the above conditions.
In addition, although glass beads were used as the regular spherical particles, the regular spherical particles are not limited thereto, and may include, for example, stainless steel balls, ceramic balls, steel balls, and ferrite balls in addition to the blast material described above. Is also good. However, since steel balls and ferrite spheres are magnetic materials, they are not very suitable for blasting by incorporating a permanent magnet member into a developer carrier.

In the present invention, in order to more accurately reflect the influence of the above-described blast processing, it is preferable to perform the above-described blast processing after polishing the surface of the developer carrying member in advance. As the pretreatment of the surface, various conventionally known treatment methods can be applied, and diamond polishing is preferably mentioned. This diamond polishing can be performed according to a conventional method or according to it.

The form of the developer carrier is not particularly limited as long as toner can be supplied to the image carrier, but is preferably formed of a non-magnetic and conductive material. As such a material, for example, stainless steel or aluminum can be preferably exemplified. In the case where the surface roughening treatment is performed by the above-described blast method using the exemplified materials, the material of the developer carrying member is preferably aluminum for the reason of easiness of processing.

However, when the developer carrier is formed of a material having excellent workability such as aluminum, the wear resistance of the developer carrier is reduced. Therefore, in the present invention, a layer having a sufficient hardness is provided on the surface of the developer carrier (including pretreatment such as diamond polishing as necessary) which has been subjected to surface roughening treatment by blast treatment with the above-mentioned regular spherical particles. More preferably, it is formed.

The layer is not particularly limited as long as it has sufficient hardness to supplement the wear resistance of the developer carrying member, and is nonmagnetic and conductive. Examples of such a layer include metal plating of a metal or alloy containing a simple substance or another element such as Ni-P, Ni-B, and Cr, a resin layer in which crystalline graphite or conductive carbon is dispersed, and the like. Can be exemplified. This layer may be properly used depending on the material or the like to be used, and can be formed according to a conventional method. The resin used for the resin layer may be any resin that exhibits sufficient physical properties in terms of hardness, such as a phenol resin.

As plating applicable to the present invention, there is electroless plating. As the electroless plating, for example, any one of electroless Ni-P, electroless Ni-B plating, electroless Pd-P plating, and electroless Cr plating may be used, but is not limited thereto. Absent. The characteristics of electroless plating are that, in other plating, for example, electrolytic plating such as electrolytic Ni plating, plating is more likely to be attached to the edge portion and plating thickness is more variable than in plating, so that the plating thickness is more uniform and the shape is spherical. There is an advantage that the roundness caused by the collision of particles can be maintained. In addition, there is an advantage that the adhesion is good, plating can be performed even in a deep hole, and there is no unevenness on the surface, and a smoother surface can be obtained. From the above, by performing electroless plating, it is possible to eliminate fine jaggedness existing on the surface after blasting while maintaining the surface shape after blasting by the fixed spherical particles, and to achieve smoothness without microscopic irregularities It is possible to obtain a surface. However, if the thickness of the plating is too large, it may be too smooth and the transportability of the developer carrying member may be reduced. Therefore, the plating thickness is preferably set to 20 μm or less, which is a range in which the shape generated by the collision of the fixed spherical particles can be maintained to some extent.

A magnetic field generating means is provided inside the developer carrier. The magnetic field generating means is provided with a first magnetic pole provided downstream of the developing area in the developer conveying direction, and a first magnetic pole. And a second magnetic pole having the same polarity as the first magnetic pole is provided on the downstream side in the transport direction, so that a new developer accommodated in the developing device and supplied to the developer carrier is supplied to the surface of the developer carrier. It is preferable in order to carry uniformly.

Further, if a repulsion pole is provided between the first magnetic pole and the second magnetic pole to substantially eliminate the magnetic force generated by these magnetic poles, the developer returning from the developing area is discharged from the surface of the developer carrier. Since it is easy to be detached, it is even more preferable to uniformly carry the new developer on the surface of the developer carrying member.

The magnetic field generating means is not particularly limited as long as it generates at least a magnetic force sufficient to support the magnetic carrier on the surface of the developer carrier. The magnetic field generating means may be a means for permanently generating a magnetic field, such as a generally-known magnet, or a means for generating a magnetic field intermittently or arbitrarily, such as an electromagnet. . Further, the magnetic field generating means is provided on the surface of the developer carrier,
It is preferable that the magnetic pole is set to an appropriate value according to the loading or release of the developer.

The first magnetic pole and the second magnetic pole may be N-pole or S-pole.
It is one of the poles, and is a magnetic pole for carrying the developer. More specifically, the first magnetic pole is a magnetic pole for carrying the developer returned from the developing area, and the second magnetic pole is a magnetic pole for carrying a new developer supplied from inside the developing device. The first magnetic pole and the second magnetic pole need only be the same magnetic pole, and may have the same magnetic force or may have different magnetic forces.

The repulsive pole is provided between the first magnetic pole and the second magnetic pole when the magnetic carrier is conveyed from the first magnetic pole to the second magnetic pole, so that the magnetic carrier can be released from being carried by both magnetic poles. Anything may be used as long as it can eliminate the magnetic force, and it may be one that blocks the influence of the magnetic field due to both magnetic poles between the first and second magnetic poles, or one that cancels the influence of the magnetic field due to both magnetic poles between both magnetic poles. .

The developing device of the present invention may be provided on the image carrier so that the developer contacts the image carrier to develop the electrostatic latent image, or the developer may be provided on the image carrier. It may be provided that the electrostatic latent image is developed without contact. It is preferable to provide an electric field forming means for forming an alternating electric field between the image carrier and the developer carrier in the developing device in order to improve development efficiency. As the electric field forming means, a conventionally known one can be used. For example, a power supply for applying a voltage to the developer carrier can be exemplified, and the applied voltage may be any voltage including an AC voltage.

The developer used in the developing device of the present invention is:
A two-component developer containing a non-magnetic toner and a magnetic carrier. As the non-magnetic toner and the magnetic carrier, conventionally known non-magnetic toners and magnetic carriers can be used, and the production and the measurement of the particle size can be performed according to a conventional method. Further, it is preferable that the mixing ratio of the non-magnetic toner and the magnetic carrier is appropriately set according to the type and physical properties of the toner and the carrier to be used and the required image quality.

The non-magnetic toner has a weight average particle size of 5 to 5.
A thickness of 9 μm is preferable for obtaining a high-quality image. If the weight average particle size of the non-magnetic toner is smaller than the above range, fogging and scattering due to durability become a problem, and it tends to be difficult to obtain a stable image over a long period. There is a problem that image quality is deteriorated due to scattering at the time of transfer, and it tends to be difficult to obtain high image quality from the beginning.

It is preferable that the non-magnetic toner has a uniform particle size and shape in order to prevent intrusion or locking into the minute recesses. The non-magnetic toner preferably has a spherical shape. Particularly preferred. Such a non-magnetic toner is preferably a polymerized toner manufactured by, for example, an emulsion polymerization method or a suspension polymerization method. Further, the toner can be adjusted to a desired particle size and particle size distribution by classifying the toner and selecting or mixing toner having an appropriate particle size.

The magnetic carrier is not particularly limited as long as it can carry a non-magnetic toner. The magnetic carrier preferably has a weight average particle size of 20 to 60 μm in order to carry the non-magnetic toner. If the weight average particle size of the magnetic carrier is smaller than the above range, adhesion of the magnetic carrier to the photoreceptor tends to be a problem, and if the weight average particle size is larger than the above range, deterioration of image quality due to rubbing of ears of the magnetic carrier becomes a problem. In particular, there is a tendency that it is difficult to reproduce a low-density region uniformly without any roughness. The magnetic carrier may be one whose surface has been subjected to a hydrophobic treatment.

The developer may contain other particles in addition to the non-magnetic toner and the magnetic carrier. Examples of such particles include particles for controlling or assisting the charging characteristics of the non-magnetic toner, and particles for improving the fluidity of the non-magnetic toner or the magnetic carrier.

The developing device of the present invention is not particularly limited as long as it has the above-mentioned developer carrier, but may have other conventionally known structures as appropriate. Such other configurations include, for example, a developing container for containing a developer, a stirring unit for stirring the developer in the developing container, a toner replenishing unit for replenishing consumed non-magnetic toner, A developer regulating member that regulates the amount of the developer carried on the surface of the developer carrier can be exemplified.

The image forming apparatus used in the present invention is not particularly limited as long as it has means for forming an electrostatic latent image corresponding to an image information signal on an image carrier, and has the developing device of the present invention described above. Not done. Therefore, various conventionally known configurations can be appropriately provided.

The image forming apparatus may employ an image forming method in which an electrostatic latent image is visualized with a developer. Such an image forming method includes, for example, an electrostatic latent image on a photosensitive drum. Forming and developing a latent image, then developing the electrostatic latent image to form a toner image, and transferring and fixing the toner image to a recording material with or without an intermediate to form an image And an electrostatic recording method in which an electrostatic latent image is formed on a recording material, developed, and the image is fixed to form an image. The image carrier only needs to carry an electrostatic latent image, regardless of whether or not the image is fixed to the image carrier.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a developing device according to the present invention will be described below with reference to the accompanying drawings. The developing device is used, for example, in an image forming apparatus as described below, but the present invention is not necessarily limited to this embodiment.

<Embodiment 1> FIG. 1 is an enlarged view of one station of Y, M, C and K in the full-color image forming apparatus as shown in FIG. Y,
The stations M, C, and K have almost the same configuration.
In a full-color image, yellow (Y),
Magenta (M), Cyan (C), Black (K)
Is formed. In the following description, for example, if there is the developing device 1, the developing device 1Y, the developing device 1M, the developing device 1C, and the developing device 1K in each of the Y, M, C, and K stations are commonly referred to.

The configuration of the entire image forming apparatus will be described. As shown in FIG. 2, the image forming apparatus includes a photosensitive drum 4 serving as an image carrier and a primary charger 21 for charging the photosensitive drum 4.
A light emitting element 22 for forming an electrostatic latent image on the surface of the charged photosensitive drum 4, and a developer for supplying the developer to the photosensitive drum 4 on which the electrostatic latent image has been formed, thereby developing the electrostatic latent image to form a toner. A developing device 1 for forming an image, a transfer charger 23 for transferring a toner image on the photosensitive drum 4 to a transfer sheet 24 with or without an intermediate transfer member, and a transfer sheet 24 for carrying an unfixed toner image
Paper transport sheet 27 for transporting the paper to the next stage, and transfer paper 24
1 is an electrophotographic image forming apparatus including a fixing device 25 for fixing an unfixed toner image on the photosensitive drum 4 and a cleaning device 26 for removing transfer residual toner remaining on the photosensitive drum 4 after transfer.

Next, the operation of the entire image forming apparatus will be described with reference to FIG. The photosensitive drum 4 serving as an image carrier is provided rotatably, and the photosensitive drum 4 is attached to a primary charger 21.
Light-emitting element 22 such as a laser
To form an electrostatic latent image by exposure with light modulated according to the information signal. The electrostatic latent image is visualized by the developing device 1 as a toner image in a process described below. Next, the toner image is transferred to the transfer paper 24 conveyed by the transfer paper conveyance sheet 27 by the transfer charger 23 and further fixed by the fixing device 25 to obtain a permanent image. The transfer residual toner on the photosensitive drum 4 is removed by the cleaning device 26.

Next, the configuration of the developing device 1 will be described. As shown in FIG. 1, the developing device 1 is arranged to face the photosensitive drum 4 and has a developing container 2 for containing a developer.
A developing sleeve 3 which is a developer carrying member for carrying the developer in the developing container 2 and transporting the developer to the photosensitive drum 4; and a spike height regulating member for regulating the amount of the developer carried on the developing sleeve 3. It has a blade 5 and a toner replenishing tank 6 for replenishing the developing container 2 with toner contained in the developer. The developing sleeve 3 and the photosensitive drum 4 are connected to a developing bias power supply (not shown) as an electric field forming means.

The developing container 2 is divided into two spaces by a partition, and a stirring screw 8 is provided in each space. Each of these spaces contains a two-component developer containing a non-magnetic toner and a magnetic carrier. Inside the developing sleeve 3, a magnet 7 as a magnetic field generating means is fixed. In the vicinity of the opening of the developing container 2, a developer reservoir 10 surrounded by the developing sleeve 3, the blade 5 and the developing container 2 is formed.

Next, the operation of the developing device 1 will be described with reference to FIG. The developing container 2 is open toward the photosensitive drum 4, and the developing sleeve 3 is rotatably disposed so as to be partially exposed at the opening. The developing sleeve 3 is made of a non-magnetic material, and has an uneven surface, and forms a developing area between the developing sleeve 3 and the photosensitive drum 4, and rotates in a direction indicated by an arrow in FIG. 1 during a developing operation. The developing sleeve 3 containing the magnet 7 carries and transports the layer of the two-component developer, the thickness of which is regulated by the blade 5, from the developer reservoir 10 to the developing area, and the toner transfers the developer to the photosensitive drum 4 in the developing area. The supplied electrostatic latent image formed on the photosensitive drum 4 is developed. Toner corresponding to the amount of toner consumed in image formation is supplied from the toner supply tank 6.

The magnet 7 is composed of five poles. The developer stirred by the stirring screw 8 is restrained on the developing sleeve 3 by the magnetic force of the transport magnetic pole (pumping pole) N2 for pumping, and then regulated. Magnetic pole (S2) and blade 5
The developer is transported while forming a magnetic brush by forming a layer of the developer. Next, the developer is transported to the developing area by the magnetic force of the transport magnetic pole N1 and the rotation of the developing sleeve 3. Next, the toner is supplied to the photosensitive drum 4 in a developing area facing the photosensitive drum 4 by the action of an electric field generated by the magnetic pole S1 and the developing bias power supply, and develops the electrostatic latent image formed on the photosensitive drum 4.

The developer after developing the electrostatic latent image on the photosensitive drum 4 in the developing area is conveyed from the developing area into the developing container 2 by the magnetic force of the take-in pole N3 and the rotation of the developing sleeve 3. The take-in pole N3 and the pumping pole N2 are of the same polarity, and a region (repulsion pole, not shown) where the magnetic force is approximately 0 Gauss is provided between the two magnetic poles. As a result, the developer after developing the electrostatic latent image is stored in the developing container 2 without being continuously drawn up and restrained by the pole N2.

In the case of the configuration in which the repelling pole is provided as in the present embodiment, since the rotation of the developer is reduced by the repelling pole, the toner hardly adheres to the surface of the developing sleeve 3 and stays there. Has the effect of reducing the fusion of the toner. Therefore, when the magnet 7 having the repulsive pole and the developing sleeve 3 having the surface configuration described below are used in combination as in this embodiment, the developing sleeve 3
It is effective in reducing pollution.

Next, the characteristic portion of this embodiment will be described in more detail. In the present embodiment, a non-magnetic material is used as the material of the developing sleeve 3, and the surface of the developing sleeve 3 is provided with irregularities to impart a developer conveying force. However, as described in the conventional example, in the roughened developing sleeve, depending on the state of the roughened surface, the toner or components in the toner easily adhere to the uneven portions of the roughened surface and fuse, and the surface is roughened. Contamination may occur.

Therefore, for some developing sleeves,
SUS or aluminum is used as the material of the developing sleeve, and blast processing is performed using amorphous alumina particles (ARD) or spherical glass bead particles (FGB) as abrasive grains.
The surface was subjected to a roughening treatment, and the surface roughness was measured.

For measuring the surface roughness, a contact type surface roughness meter (manufactured by Kosaka Laboratory Co., Ltd .: Surfcoder SE-330)
0) was used. This measuring device can simultaneously measure the ten-point average roughness Rz of the surface of the developing sleeve and the average peak-to-valley spacing Sm in a single measurement. The measurement conditions are standard settings,
Two modes of detailed settings were used. The standard settings are a cutoff value of 0.8 mm, a measurement length of 2.5 mm, a feed speed of 0.1 mm / sec, and a height magnification of 5000 times.
The width magnification is 50 times, the detailed settings are cut-off value 0.08 mm, measurement length 0.25 mm, feed speed 0.05 mm / sec, height magnification 5000 times, width magnification 5000 times.

Here, Rz is a ten-point average roughness according to JIS B 0601, and qualitatively represents a height difference between an uneven peak and a valley. Further, Sm is the first peak crossing the average line S of the cross-sectional curve X at a portion cut out by a reference length (measured length) L from the cross-sectional curve X of the surface subjected to the surface roughening treatment as shown in FIG. The interval from the crossing point from the hill to the valley to the crossing point from the next peak to the valley is S1, and the interval between the crossing points after that is S1.
2, S3,..., Sn (n indicates the total number of traversing points in the reference length) and is an arithmetic average thereof, and is represented by the following equation.

## EQU1 ## Sm = (S1 + S2 +... + Sn) / n Sm qualitatively represents the average distance between a peak and an adjacent peak. Rz,
For the Sm data, the measured values at the standard settings were used.

In the surface profile, on the curve forming peaks and valleys, the curvature of the curve is significantly different.
The measurement mode of the detailed setting was used as a condition for confirming the abundance of the concave portion having a width of 1 μm to 10 μm and a depth of 0.2 μm or more.

The information on the surface roughness was compared with the degree of contamination on the developing sleeve after 10,000 sheets were used for a long time. At this time, a non-magnetic toner having a weight average particle diameter of 8 μm and a magnetic carrier having a weight average particle diameter of 40 μm (T / C = 8
/ 92) using a two-component developer.
As a method for evaluating the contamination density, the reflected light on the surface of the developing sleeve before and after use was measured using a reflection type densitometer, and the optical density difference ΔD was used as the contamination density.

In Experimental Example 1 (Comparative Example 1), the material was SU.
The developing sleeve (S) is made of amorphous alumina particles (AR
D # 400) to roughen the surface. The surface condition of this developing sleeve is Rz = 3 μm, S
m 2 = 13 μm. FIG. 4 shows the profile of the surface of the developing sleeve. As shown in FIG.
When the surface is roughened at 00, the curves forming the peaks and valleys are not clear, and the width is 2 μm to 10 μ everywhere on the surface.
m, and a concave portion having a depth of 0.2 μm or more (portion indicated by ↓ in FIG. 4) exists, and the number thereof is about 30 at intervals of 100 μm.

When such a developing sleeve was used, as shown in Table 1, after the long-term use of 10,000 sheets, the toner was fused to the surface of the developing sleeve. In this case, regarding the transportability of the developer, although the Rz of the surface of the developing sleeve is small, the friction coefficient of the surface is increased by blasting using amorphous alumina particles as a surface profile. As a result, No defective transport of the developer was observed. The present inventors have considered that the fusing phenomenon of the toner occurs due to the following reasons.

In the two-component developing system as in this embodiment, the developing sleeve 3 transports the magnetic carrier to which the toner is attached to the developing area while holding the magnetic carrier on the surface. Further, when the toner particle size is reduced, the amount of toner having a particle size of 2 μm or less increases. It is considered that such a toner having a small particle diameter easily sinks into a concave portion having a width of 1 μm to 10 μm and a depth of 0.2 μm or more, adheres to the surface of the developing sleeve, and stays.

In particular, when the average peak interval Sm on the surface of the developing sleeve is extremely smaller than the weight average particle diameter of the magnetic carrier as in Experimental Example 1 (Comparative Example 1), even if the toner enters a fine concave portion by pressing the carrier. , The carrier cannot enter the recess. As a result, it is considered that this toner adheres while being caught in the concave portion of the developing sleeve surface without a chance to come into contact with the carrier in the process of circulating the carrier, and will be fused during long-term use. .

As described above, the present inventors have determined that the average peak-to-peak spacing Sm on the surface of the developing sleeve is extremely smaller than the weight average particle diameter of the magnetic carrier, and that the fusion of the toner Next, in Experimental Example 2 (Comparative Example 2), a developing sleeve made of aluminum was used as the experimental example 2 (Comparative Example 2), and amorphous alumina particles (ARD # 150) having a larger particle diameter than Experimental Example 1 (Comparative Example 1) were used. The surface was roughened by blasting. The surface condition of this developing sleeve was Rz = 10 μm, and the average peak interval Sm was Sm = 32 μm, which is almost the same as the carrier weight average particle diameter of 40 μm. When the developing sleeve was durable, the contamination level was reduced as shown in Table 1.

Further, as a result of a detailed study including the type of carrier, the average peak interval Sm is D / 3 ≦ Sm ≦ 6D, preferably D / D, where D is the weight average particle diameter of the carrier.
It was found that it was better to be in the range of 2 ≦ Sm ≦ 3D. When the average peak interval Sm is equal to or more than D / 3, the toner that has entered the valley on the surface of the developing sleeve as described above also
As the carrier circulates, the carrier comes into contact with the toner, so that the toner adheres to the carrier and is conveyed. As a result, the toner does not adhere to and remains on the surface of the developing sleeve, thereby reducing the contamination level. . However,
When the average peak interval Sm exceeds 6D, the developer transportability of the developing sleeve is reduced.

As described above, by adjusting the average mountain interval Sm, the level of the contamination is reduced. However, when comparing the image quality, image defects are still likely to occur, and the contamination level needs to be further reduced. The following reasons were considered as the reasons for the image failure in this experimental example. FIG. 5 shows a profile obtained by measuring the developing sleeve surface used in Experimental Example 2 with detailed settings.

In this case, unlike the experimental example 1, peaks and valleys can be confirmed. However, on the curve that forms the peaks and valleys, there are recesses (portions indicated by ↓ in FIG. 5) having a width of 1 μm and a depth of 0.2 μm or more that are significantly different from the curvature of the curve, and the number thereof is 100 μm. Approximately 10 during the interval.
Also in this case, even if the toner having a small particle diameter enters the concave portion, the carrier cannot enter the minute concave portion. As a result, in the process of circulating the carrier, the toner adheres to the minute recesses on the surface of the developing sleeve without a chance to come into contact with the carrier and adheres to the nucleus during long-term use. It is thought to lead to wearing. Therefore, the following experiment was performed.

As an experimental example 3, the surface of the developing sleeve made of aluminum was roughened using spherical glass bead particles (FGB # 300) having a weight average particle diameter of 70 μm, and Rz = 8.5 μm. The study was performed using a developing sleeve with an average peak interval Sm = 34 μm. As a result, after the long-term use of 10,000 sheets, the level of contamination of the developing sleeve is shown in Table 1, even though the average peak interval Sm of the surface is the same as that of the developing sleeve of Experimental Example 2 (Comparative Example 2) described above. Thus, it was further reduced as compared with Experimental Example 2 (Comparative Example 2). FIG. 6 shows the profile of the surface of the developing sleeve.

Experimental Example 1 of Blasting Using ARD
When the surface shapes of the developing sleeves of Comparative Examples 1 and 2 and Comparative Example 2 and the developing sleeve blasted using FGB # 300 used this time are compared, as shown in FIG. 6, FGB # 300 (weight) This developing sleeve blasted using an average particle diameter of 70 μm has a curve on a curve that forms peaks and valleys and is significantly different from the curvature of the curve.
There are almost no recesses having a width of 1 μm and a depth of 0.2 μm or more (indicated by ↓ in FIG. 6), the number of which is about 3 to 4 in an interval of 100 μm, and a very shallow depth. With such a surface, it is considered that there is almost no place where the toner having a small particle diameter enters, and as a result, there are no fusion nuclei and contamination is reduced.

In Experimental Example 4, the surface of the developing sleeve made of aluminum was roughened using spherical glass bead particles (FGB # 100) having a weight-average particle diameter of 180 μm to obtain a ten-point average roughness Rz. = 14 μm, average peak interval Sm = 6
It was set to 0 μm. As shown in FIG. 7, the profile of the surface of the developing sleeve is represented by a curve forming peaks and valleys.
This shows that there are approximately two concave portions having a width of 2 μm and a depth of 0.2 μm or more, which are significantly different from the curvature of the curve, at intervals of 100 μm. As a result of an examination using this developing sleeve, the level of contamination of the developing sleeve after the long-term use of 10,000 sheets is almost the same as that of the above-described Experimental Example 3, but the developer transportability is improved. As shown, the layer thickness of the developer on the developing sleeve could be made more stable and uniform.

[0084]

[Table 1] ○: good ×: bad

As shown in Experimental Example 4 conducted this time, it was found that when the ten-point average roughness Rz was increased, the transportability could be improved while the surface of the developing sleeve was kept smooth. In general, it is considered that increasing the value of the ten-point average roughness Rz makes it easier for the toner to be caught in the concave portions on the surface, thereby deteriorating the level of development sleeve contamination. However, on the curve that forms peaks and valleys, If the number of concave portions having a width of 1 μm to 10 μm and a depth of 0.2 μm or more, which is significantly different from the curvature of the concave portion, is kept small so as to be less than 10 in the interval of 100 μm, the value of the ten-point average roughness Rz is reduced. Even if it is increased to some extent, the level of contamination of the developing sleeve does not deteriorate.

As a result of a detailed study including the type of carrier, etc., the weight average particle diameter D of the magnetic carrier was 1/1/3.
It is sufficient if the ten-point average roughness Rz is set in a relationship of 10 times to 1/2 times. In the case of D / 10 or more, the magnetic carrier is caught by the valley on the surface, and as a result, the transportability of the developer is improved. However, if Rz is greater than D / 2, the irregularities on the surface of the developing sleeve become clearly visible, and the layer of the developer becomes uneven by reflecting the irregularities, thereby affecting the image.

Until now, after the raw tube was cut, a developing sleeve whose surface was roughened by blasting using amorphous alumina particles (ARD) or spherical glass bead particles (FGB) as abrasive grains was used. As described in the example, the surface subjected to the blasting after the cutting has a fine jagged state reflecting the surface roughness at the time of the cutting. When such minute jaggies exist, the toner having a small particle diameter contained in the toner is caught and attached to the minute grooves,
It tends to be in a fused state, and the developing sleeve is likely to be contaminated.

As a method for solving such a problem, the surface of the developing sleeve tube is roughened by performing diamond polishing after cutting and then blasting. As a result, contamination of the developing sleeve due to surface roughness during cutting is improved. This is because the surface of the developing sleeve tube has been modified to a mirror-like surface state in which there is almost no jaggedness at the time of cutting due to diamond polishing and there is no jaggedness even in microscopic view.

As described above, in this embodiment, the average peak-to-peak spacing Sm of the irregularities on the surface of the developer carrier is 1/3 to 6 times the weight average particle diameter D of the magnetic carrier in the two-component developer. D / 3 ≦ Sm ≦ 6D), and the ten-point average roughness Rz of the surface is 1/1 of the weight average particle diameter D of the magnetic carrier.
The relationship is set to 0 times to 1/2 times, and furthermore, on the surface profile, on a curve forming peaks and valleys, the curvature is significantly different from the curvature of the curve, and the width is 1 μm to 10 μm and the depth is 0.2 μm. By making the amount of the above concave portions less than 10 in the interval of 100 μm, the toner is prevented from being embedded in the concave portions on the surface of the developing sleeve by the carrier, and the developing sleeve is not contaminated by the fusion of the toner. As a result, it has become possible to stably obtain high-quality images for a long period of time.

Here, a method for measuring the weight average particle diameter of the carrier and the toner will be described. The method for measuring the weight average particle size of the carrier used in the present invention is as follows. 1. Weigh about 100 g of sample to the nearest 0.1 g. 2. As the sieve, a standard sieve of 100 to 400 mesh (hereinafter simply referred to as “sieve”) is used, and 100 mesh (particle size 149 μm), 145 mesh (particle size 105 μm), and 200 mesh (particle size 74) from the top.
μm), 250 mesh (particle size 63 μm), 35
The layers are stacked in the order of 0 mesh (particle size 44 μm) and 400 mesh (particle size 37 μm). 3. Using a vibrator, the number of horizontal turns is 285 ± 6 per minute.
And shake at 150 ± 10 times per minute for 15 minutes. 4. After sieving, weigh the iron powder in each sieve and tray to the nearest 0.1 g. 5. Calculated to the second decimal place by weight percentage, JIS-Z8
401 rounds to the first decimal place.

At this time, the dimensions of the sieve frame were such that the inner diameter above the sieve surface was 200 mm, the depth from the upper surface to the sieve surface was 45 mm, and the total weight of the samples in each part was the sample taken first. Not more than 99% of the weight of The weight average particle diameter is obtained from the above-mentioned constant value on the particle size distribution side according to the following equation. Weight average particle size (μm) = 1/100 × ｛(remaining amount of 100 mesh sieve) × 140 + (remaining amount of 145 mesh sieve) ×
122+ (remaining amount of 200 mesh sieve) × 90 + (250
Remaining mesh sieve) × 68 + (remaining 350 mesh sieve) × 52 + (remaining 400 mesh sieve) × 38 + (total sieve passing amount) × 14 通過

In the present invention, the weight average particle diameter of the toner was measured, for example, by the following measuring method. Coulter counter TA-II type (manufactured by Coulter)
Alternatively, an interface (manufactured by Nikkaki) and a CX-i personal computer (manufactured by Canon) that output a number average distribution and a volume average distribution are connected to each other using a Coulter Multisizer (manufactured by Coulter), and the electrolyte is primary sodium chloride. Prepare a 1% NaCl aqueous solution using.

The measuring method is as follows.
In 50 mL, 0.1 to 5 mL of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant, and 0.5 to 50 mg of a measurement sample is further added.

The electrolyte in which the sample was suspended was mixed with an ultrasonic disperser for 1 hour.
Perform a dispersion treatment for ~ 3 minutes, and
Using type II, the particle size distribution of particles of 2 to 40 μm is measured by using a 100 μm aperture as the aperture, and the distribution is determined to obtain the weight average particle size of the sample.

<Embodiment 2> In this embodiment, after the surface of the developing sleeve 3 is roughened in the same manner as in Embodiment 1, Ni-P plating, Ni-B plating, or C
The feature is that the surface of the developing sleeve is formed by coating with r plating.

On the surface of the developing sleeve 3, Ni-P, Ni-
Coating with B or Cr plating not only facilitates the control of the surface roughness, but also has the effect of improving the wear resistance of the developing sleeve 3. In addition, there is also an effect of smoothing out a fine jagged surface generated when cutting the developing sleeve as described in the first embodiment.

When aluminum is used for the material of the developing sleeve 3, the cost can be reduced compared with stainless steel. However, the hardness of the surface of the developing sleeve 3 is low. And the life of the developing sleeve 3 is shortened. This is because the surface of the developing sleeve 3 made of Ni-P, Ni-
When coating with B or Cr plating, the surface hardness is higher than that of aluminum, and the life of the developing sleeve 3 can be extended.

The improvement in the wear resistance of the surface of the developing sleeve 3 will be further described.
When using Si (amorphous silicon) drum, in order to prevent the flow phenomenon of image quality at the time of initial use,
The heater is contained in the a-Si drum. When the developing sleeve 3 is made of stainless steel, it has a low thermal conductivity and is easily deformed by the heat of the drum heater. To avoid thermal deformation due to the drum heater, the developing sleeve 3
Can be made of aluminum with high thermal conductivity,
Aluminum has lower wear resistance than stainless steel. Ni-P, Ni-
By coating with a plating of B or Cr, the surface is hardened and the wear resistance can be easily improved.

<Embodiment 3> In this embodiment, as in the case of Embodiment 2, the surface of the developing sleeve is subjected to a surface roughening treatment and then a coating is applied thereon to obtain a desired surface state. The difference is that the example is coated with a resin layer containing crystalline graphite and conductive carbon. The coating of the resin layer was performed using Ni-P, Ni-B,
Alternatively, as in the case of plating with Cr, it is possible to easily form a desired surface shape and to harden the developing sleeve.

[0100]

As described above, according to the present invention,
The average peak-to-valley spacing (S
m) is set to 1/3 to 6 times (D / 3 ≦ Sm ≦ 6D) the weight average particle diameter (D) of the magnetic carrier in the two-component developer, and further, the ten-point average roughness (Rz) ) Is set to a relation of 1/10 to 1/2 times the weight average particle diameter (D) of the magnetic carrier, and the surface profile has a curve having peaks and valleys. The toner is embedded in the recesses on the surface of the developing sleeve by making the abundance of the recesses having a width of 1 μm to 10 μm and a depth of 0.2 μm or more that are significantly different from the curvature less than 10 in the interval of 100 μm. Thus, contamination of the developing sleeve due to fusion of the toner does not occur, thereby making it possible to stably obtain a high-quality image for a long period of time.

When the surface of the developing sleeve is subjected to Ni-P plating, Ni-B plating, or Cr plating, or when coated with a resin layer containing crystalline graphite and conductive carbon, the developing sleeve is In addition to effectively improving the wear resistance of the surface,
The surface of the developing sleeve can be easily controlled.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a developing device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an image forming apparatus using a developing device according to one embodiment of the present invention.

FIG. 3 is an enlarged view of the surface of the developing sleeve of FIG. 1 for explaining an average peak interval.

FIG. 4 is an explanatory diagram in which the surface of the developing sleeve of Experimental Example 1 is enlarged in order to explain an average peak interval.

FIG. 5 is an enlarged explanatory view of a surface of a developing sleeve of Experimental Example 2 for explaining an average peak interval.

FIG. 6 is an enlarged explanatory view of a surface of a developing sleeve of Experimental Example 3 for explaining an average peak interval.

FIG. 7 is an enlarged explanatory view of a surface of a developing sleeve of Experimental Example 4 for explaining an average peak interval.

FIG. 8 is an enlarged explanatory view of a surface of a developing sleeve for describing one embodiment of the present invention.

FIG. 9 is an enlarged explanatory view of a surface of a developing sleeve for describing one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Developing device 2 Developing container 3 Developing sleeve (developer carrier) 4 Photosensitive drum (image carrier) 5 Blade (spike height regulating member) 6 Toner replenishing tank 7 Magnet (magnetic field generating means) 8 Stirring screw 10 Developer reservoir 21 Primary charger 22 Light-emitting element 23 Transfer charger 24 Transfer paper 25 Fixing device 26 Cleaning device 27 Transfer paper transport sheet Y Symbol representing yellow in full-color image forming device M Symbol representing magenta in full-color image forming device C In full-color image forming device Symbol for cyan K Symbol for black in full-color image forming apparatus L Reference length S Average line of cross-sectional curve X Cross-sectional curve indicating surface of developing sleeve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomoyuki Sakamaki 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 BA15 EA05 FA02 2H031 AC10 AC11 AC19 BA09 2H077 AD06 EA03 FA03 FA14 FA16 FA19 GA03

Claims (16)

[Claims] 1. An image forming apparatus comprising: means for forming an electrostatic latent image corresponding to an image information signal on an image carrier;
In order to form a toner image by developing the electrostatic latent image on the image carrier, a developer carrier that carries a two-component developer containing a non-magnetic toner and a magnetic carrier and transports the developer to a development area is provided. In the developing device, the surface of the developer carrier is provided with irregularities, and the average mountain interval (Sm) of the irregularities is 1/3 to 6 times (D) the weight average particle diameter (D) of the magnetic carrier. / 3 ≦ Sm ≦ 6D), and the ten-point average roughness (Rz) of the surface of the developer carrier is 1/10 to 1/2 of the weight average particle diameter (D) of the magnetic carrier.
The number of recesses having a width of 1 μm to 10 μm and a depth of 0.2 μm or more is less than 10 in an interval of 100 μm in the profile of the surface of the developer carrying member. Developing device. 2. The developer carrier according to claim 1, wherein the surface of the developer carrier is formed of aluminum, and the surface of the developer carrier is formed by blasting using spherical glass beads. The developing device as described in the above. 3. The surface of the developer carrying member is roughened to form irregularities, and further coated, so that the average peak-to-peak spacing (Sm) of the irregularities on the surface of the developer carrying member is reduced.
The developing device according to claim 1, wherein the ten-point average roughness (Rz) is adjusted. 4. Ni-P, on the surface of the developer carrying member
4. The developing device according to claim 3, wherein a plating layer containing at least one selected from Ni-B and Cr is coated. 5. The developing device according to claim 1, wherein the material of the developer carrier is stainless steel or aluminum. 6. A magnetic field generating means is provided inside the developer carrier. The magnetic field generating means is provided with a first magnetic pole provided downstream of the developing region in a developer transport direction, The developing device according to claim 1, further comprising a second magnetic pole provided at a downstream side of the magnetic pole in the transport direction and having the same polarity as the first magnetic pole. 7. Between the first magnetic pole and the second magnetic pole,
7. The developing device according to claim 6, further comprising a repulsion pole for substantially eliminating the magnetic force generated by these magnetic poles. 8. The developing device according to claim 1, further comprising an electric field forming means for forming an alternating electric field between the image carrier and the developer carrier. 9. The developer carrier has a weight average particle diameter (d) of not less than the weight average particle diameter (D) of the magnetic carrier and not more than 10 times the weight average particle diameter (D ≦ d ≦ 10D). The developing device according to any one of claims 1 to 8, wherein a surface of the developing device is blasted with regular spherical particles. 10. The developer carrier has a surface having a ten-point average roughness (Rz) of a weight average particle diameter (D) of the magnetic carrier.
The developing device according to any one of claims 1 to 9, wherein the ratio is not less than 1/6 and not more than 1/2 (D / 6≤Rz≤D / 2). 11. The developer carrier according to claim 1, wherein the surface of the developer carrier has been subjected to diamond polishing and then the surface has been subjected to blasting with regular spherical particles. Developing device. 12. The developer carrier according to claim 1, wherein the surface of the developer carrier is subjected to blasting with regular spherical particles, and then the surface is further subjected to electroless plating. The developing device as described in the above. 13. The developer carrier according to claim 1, wherein the developer carrier is made of aluminum or stainless steel.
3. The developing device according to any one of 2. 14. An electroless plating method comprising:
13. An electroless Ni-B plating, an electroless Pd-P plating, or an electroless Cr plating.
The developing device as described in the above. 15. The method according to claim 15, wherein the shaped spherical particles are glass beads,
The developing device according to claim 1, wherein the developing device is one of a stainless steel ball and a ceramic ball. 16. The non-magnetic toner having a weight average particle size of 5
-9 μm, and the magnetic carrier has a weight average particle size of 2
The developing device according to claim 1, wherein the thickness is 0 to 60 μm.